Pump



Dec. 31, 1940.

T. v. DILLSTROM 2,227,127

PUMP

Filed June 24, 1959 s Sheets-Sheet 1 I 1 YENTQR. 2 BY M Aa ATTORNEY.

Patented Dec. 31, 1940 UNITED STATES PATENT OFFICE PUMP Application June 24. 1939, Serial No. 281.035

16 Claims.

The present invention relates to pumps and has particular reference to fuel injection pumps for internal combustion engines. Still more particularly the invention relates to fuel injection 5 pumps for mutiple cylinder engines.

In fuel injection systems as heretofore commonly used, injection of fuel to the several injectors of a multiple cylinder engine has been accomplished either through the medium of lo multiple plunger pumps, each of which operates to feed a separate injector, or through the medium of a common pressure pump from which fuel is distributed to individual lines leading to separate injectors. In some cases, individual pump units each having its own plunger, are

individually applied to the several cylinders. All

of these constructions are relatively very expensive and it has heretofore been proposed to provide an injection pump having a single plunger and barrel, ported to provide a plurality of delivery periods during one discharge stroke of the plunger, thus enabling a single pump plunger assembly to serve a plurality of cylinders. This type of pump may for convenience be referred 25 to herein as a multiple outlet pump, it being understood that where this term is employed it refers to pumps having a plurality of outlets communicating with a common pump chamber.

30 The present invention deals particularly with multiple outlet pumps and contemplates the provision of new forms of pump construction of the multiple outlet-type which in certain engine applications may more advantageously be applied 35 because of giving different injection characteristics than types heretofore proposed and which in certain instances may be cheaper to manufacture than prior forms.

Other and more detailed objects of the invention will appear in the ensuing portions of this specification in which various embodiments of new pump structure and the manner of application thereof to an engine in accordance with the invention are described by way of example.

45 In the drawings forming a part hereof:

Fig. 1 is a central section taken on lines l-| of Figs. and 6 showing a pump embodying certain features of the invention;

Fig. 2 is a section taken on line 22 of Fig. 1;

50 Fig. 3 is a section taken on line 3-3 of Fig. 1;

Fig. 4 is a transverse section of the pump shown in Fig. 1, taken on the line 44 of Fig. 5;

Fig. 5 is a section on enlarged scale of the base of the pump shown in Fig. 1, taken at right angles to the plane of Fig. 1;

Fig. 6 is a side elevation of an engine showing the pump of Fig. 1 mounted thereon;

Fig. 7 is a more or less diagrammatic fragmentary section showing another form of pump embodying features of the invention; 0

Figs. 7a and 7b are fragmentary views showing portions of pump plungers embodying features of the invention and adapted to be incorporated in a pump construction of the type shown in Fig. 8 is a view similar to Fig. 7 showing still another form of pump embodying features of the invention;

Fig. 9 is a view similar to Fig. '7 illustrating still another form of pump structure embodying features of the invention;

Fig. 10 is a more or less diagrammatic fragmentary view showing pump and pump actuating structure embodying features of the invention; and

Fig. 11 is a section taken on the line ll-ll of Fig. 10.

For a better understanding of the invention we will first consider one form of pump embodying certain principles of the invention, illustrated in Figs. 1 to 5, inclusive.

Referring now more particularly to these figures, the pump illustrated is a single cylinder pump having four outlet-s from each of which liquid is separately delivered. It is to be understood, however, that the invention is not limited to this particular kind of pump since the number of outlets supplied from a single pump chamber may be varied within the scope of the invention. For reasons hereinafter more fully appearing, experience has indicated that for mostinternal combustion engines of the injection type, four outlets supplied from a single pump chamber represents the desirable maximum so that in the case of engines having a larger number of injectors than four the number of pump units will be increased to the extent required to make it unnecessary for any one pump unit to supply more than four injectors.

The pump illustrated comprises a pump body Hi to which a head I2 is removably fixed, as by means of studs l3 (Fig. 2). To head I2 there is removably attached the pump barrel M, the barrel being advantageously secured to the head by means of a threaded collar IS. The position of the barrel is centered and fixed rotationally with respect to the head, advantageously by means of centering pins I8. The pump plunger 20 is located in the bore of the barrel I4, which bore communicates at its inner end with a bore in the head and which together with the bore in the barrel provides a pump chamber 2|. The inner end of the pump chamber is closed by means of a relief valve 22 working in a guide 24 and advantageously seating on a hardened bushing 26 clamped in position by the guide 24 which is screwed into the-head I2. Valve 22 is spring loaded by a heavy spring 28 compressed between a spring retainer 30 which bears against the upper end of valve 22 and cap 32 screwed into the upper end of the head -l.2. An inlet for liquid is provided by the connection 34 which opens into the chamber 36 in the head. Liquid is admitted to the pump chamber from chamber 36 through the spring loaded inlet valve 38 mounted in the pump head. For reasons which will hereinafter be more fully explained, the liquid, in case it is fuel, may advantageously be supplied to the pump by any suitable circulating system in quantities greater than the maximum capacity of the pump to deliver, the excess being returned to the circulating system through the outlet connection 40 leading from the chamber 38.

The pump head is provided with four outlets 42, 44, 46, and 48 advantageously spaced symmetrically around the circumference of the head as indicated in Fig. 2. Each of these outlets is provided with a spring loaded discharge valve such as valve 50 shown in Fig. 1 for the outlet 42.

The several outlets are placed in communication with the bore of the pump barrel by means of discharge passages comprising portions 42a, 44a; 46a, and 48a, respectively, located in the pump head. These portions communicate respectively with portions 42b, 44b, 46b, and 48b in the pump barrel, the latter portions, in the present embodiment, being illustrated for convenience as lying in the same axial plane.

As will be observed from Fig. 1, the passage portions 42a and 42b lie in the same plane and connect directly with each other. In order to provide for connection between the different portions of the remaining passages suitable grooves are provided in the top of the pump barrel as indicated in Fig. 3, groove 44c connecting the portions 44a and 44b, groove 46c connecting portions 46a and 46b and groove 48c connecting portions 480. and 48b. The several passages terminate at their inner ends in delivery ports 42d, 44d, 46d and 48d respectively, which ports are longitudinally spaced along the wall of the cylinder bore as indicated in Fig. 1.

The pump plunger is provided with a delivery port or recess 52 which is constantly in communication with the pump chamber 2| by way of passage 54 in the inner end of the plunger. Port 52 is defined in part by parallel control edges 56 and 58 disposed at right angles to the axis of the plunger, these control edges being connected by an oblique control edge 60.

The plunger is reciprocated by means of a cam 62 fixed to or forming an integral part of a cam member 64 hereinafter to be more fully described. Cam G2 actuates roller tappet 66, against the upper recessed face of which the lower end or foot of the pump plunger is held. Pump springs 68 and, 10 are held in compression between a spring retainer I2, bearing on the top of the tappet, and the lower ends of the barrel l4 and barrel retainer l6 respectively. A plunger adjusting member 14 is pinned to the lower end of the plunger below a shoulder on the plunger, this member having a radially extending arm 14a from which a pin '41 projects upwardly. Arm 14a projects through a slot 66a (see Fig. 4) in the upper part of the tappet and pin 14b engages a vertical slot 16 in a, control rod 18 slidably mounted in suitable bearings in the casing l0.

The cam 62 is advantageously of special form having rising cam face sections I, II, III, and IV arranged 90 apart and separated by intermediate sections of constant radius 62a, 62b, and 62c. Between the sections IV and I the cam face falls as indicated at V. The direction of rotation of the cam is as indicated by the arrow 80.

The operation of the pump is as follows, it being assumed that the plunger is in the position of rotation shown in Fig. 1, and that the pump chamber is filled with liquid. As the cam rotates from the position shown in the figure so that the tappet roller follows the rising section I, the plunger is forced inwardly on its discharge stroke. This movement of the plunger is effected with all outlets from the pump chamber closed and consequently results in a rise in the pressure of the liquid in the chamber to a high value, which is eventually sufiicient to open the relief valve 22 against the resistance of the spring 28. The value of the pressure exerted by spring 28 is chosen sufficiently high to maintain the desired maximum delivery pressure from the pump. In the case of a fuel injection pump delivering to injection nozzles the pressure required to open the relief valve may be of the order of several hundred atmospheres.

Continued movement of the punger on its discharge stroke is permitted by the opening of the relief valve and this continued movement causes the inner control edge 56 of the plunger port to pass the near edge of the cylinder port 42d, thus bringing these two ports into communication.

As soon as this occurs, delivery of the liquid through the outlet 42 is commenced, since as previously noted the pressure exerted by spring 28 is suificiently high to insure delivery pressure being obtained. Delivery through outlet 42 continues until the lower control edge 58 of the plunger port passes the delivery port 42d, this movement of the plunger being effected by the cam surface I and constituting what may be termed a delivery period on the discharge stroke of the plunger.

The control edge 58 passes out of communication with port 42d before the upper control edge 56 comes into communication with the next delivery port 44d and any movement of the plunger in discharge direction required between the time when the plunger port passes out of communication with port 42d and comes into communication with port 44d is permitted by the relief valve 22 again opening.

When the pump is utilized as a fuel injection pump it is ordinarily necessary to provide for an appreciable time interval between the termination of one delivery period and the commencement of the next delivery period, in order to properly time the injections. This time interval might be provided by spacing the several cylinder ports the required distance apart to properly time the apparatus with a plunger movin inwardly throughout its discharge stroke at constant velocity. This, however, would involve in many cases undesirable length of pump barrel and plunger, and in order to shorten the required length of these parts the cam is advantageously formed in the manner heretofore described so as to produce stepwise movement of the plunger on its discharge stroke, with little or no movement between delivery periods.

As soon as theplunger port is brought into communication with port 44d by the movement effected by the cam section II, the relief valve 22 again closes and delivery is elTected through the outlet 44, this delivery constituting the second delivery period. The second delivery period continues until the control edge 58 passes port 44d, at which time the relief valve again opens and remains open until the third delivery period is commenced by the cylinder and plunger ports 46d and 52 being brought into communication through the action of the cam section III. The previously described action is then repeated to provide for the third and fourth delivery periods through outlets 46 and 48 respectively. a

The last delivery period of the discharge stroke is effected by the cam section IV, and the ensuing suction stroke of the plunger is effected by the falling cam section V which permits the pump springs to force the plunger outwardly to the position shown in Fig. 1.

From a consideration of Fig. 1 it will be apparent that if the cam sections IIV are located on the cam to give properly spaced delivery periods, the section V can occupy only a small portion of the cam perimeter. Consequently the edge of the latter section must be steep, with resultant high speed of plunger travel on the suction stroke. If more than four delivery periods were to be provided for, the slope of the section V would result in too high suction stroke speed for most injection pumps. Consequently in most instances four outlets is the preferred maximum to be served by a single plunger.

In the operation just described it has been assumed that the plunger is in the position of rotation shown in Fig. 1. In this position the maximum quantity of liquid is delivered during each delivery period since when in this position the axial length of the plunger port which is in communication with the several cylinder ports is maximum. In order to adjust the quantity of liquid delivered during each delivery period,

the pump plunger is rotated by moving the con-.

trol rod 18, which may be automatically operated by any suitable governing mechanism or under manual control.

To decrease the quantity of liquid delivered, the rod '18 is moved so that the plunger is rotated in clockwise direction viewed from the inner end of the plunger or in other words so that the control edge 6|] turns to the left from the position shown in Fig. 1. With the plunger moved to a position so that the edge 6|! crosses the several delivery ports as the plunger moves inwardly of its discharge stroke, it will be evident that the several delivery periods will each be shortened and also that they will be shortened by delaying commencement of the delivery periods relative to the pump cycle while maintaining their termination constant relative to the.

pump cycle. Obviously the change in timing which is effected by adjustment of the plunger to vary the quantity may be altered by suitably changing the configuration of the control edges of the plunger port. For example, if the slope of the edge 60 should be made at right angles to the slope indicated in Fig. 1 it will be apparent that variation in quantity of liquid delivered during the several delivery periods would be accomplished in the same way as by the structure illustrated, but timing would in such case be varied by changing the time of termination of the delivery periods relative to the pump cycle while maintaining the commencement of the delivery periods constant relative to the pump cycle.

Since the cylinder ports are all in the same axial plane and the pin 14b slides axially in the slot 16 as the plunger moves on its discharge stroke, it will be evident that all delivery periods will be of the same duration for any given position of rotational adjustment of the plunger.

In addition to providing the advantage of simplicity and low cost of manufacture, a pump operating as above described provides the possibility of substantial advantage in the character of fuel delivery to injection nozzles. In order to secure consistent and favorable atomization through an injection nozzle it is desirable to provide as nearly as possible a constant pressure on the fuel during the injection period. In the usual form of injection pump this is difficult to obtain. In the present instance high pressure for injection may readily be built up in the pump chamber prior to the commencement of any delivery period, by proper selection of the strength of the spring controlling the pump relief valve. This being the case, the desired maximum delivery pressure can readily be maintained throughout the entire delivery period since with the present arrangement the value of delivery pressure can be determined by the relief valve spring rather than by plunger speed.

As will be apparent from Figs. 1 and 5, the pump is very compact transversely and this characteristicof the pump provides for extremely simple and inexpensive mounting of the pump on an engine in the manner shown in Figs. 5 and 6, wherein the pump is shown as being mounted by a simple flange mounting directly to the forward part of the engine and in line with thc engine cam shaft, as indicated in Fig. 6. In this figure the engine is indicated generally at 82 and has the usual conventional timing gears or chain located behind a suitable gear cover 84 secured to or forming a part of the forward end of the engine. The pump casing is secured to the gear cover 84 so that an opening 66 in the lower portion of the pump casing is in alignment with a similar opening 88 formed in the gear cover. The latter opening is in line with the end of the engine cam shaft 90 which in the present instance has been shown as having bolted thereto the cam shaft gear 92. In the embodiment illustrated. the pump cam member 64 is made in the form of a heavy spindle having a base portion 84a adapted to bear against the face of the cam shaft gear 92 and advantageously provided with a square or hexagonal projection 94 located in a similarly shaped recess 96 in the face of the gear 92 to prevent turning of the cam member 64 with respect to the cam shaft and cam shaft gear. The cam member 64 issecured in overhung relation on the cam shaft by means of the stud 98, the end of which is made accessible through a small removable cover plate H in the side of the pump casing ill.

As will be apparent from Fig. 6, the compact dimensions of the pump are such that it may readily be mounted in this position without interfering with the cooling fan or other 3135395" sories usually mounted at the forward end oi the engine and from Fig. 5 it will be apparent that the manner in which the pump is mounted, which permits the pump cam to be directly secured to the engine cam shaft, enables the usual pump cam shaft and bearings to be eliminated, thus very materially reducing the cost of the unit. Also, this type of mounting places the interior of the lower portion of the pump casing in direct communication with the interior of the engine and the pump cam, tappet, etc. may read ily be lubricated by oil from the engine lubricating system, so that no separate lubricating system within the pump is required.

As will further be apparent from Fig. 5, the construction illustrated requires no special features of engine construction and if for any reason it is desired to operate the engine without a fuel pump, all that is required is to unbolt the pump body from the engine, remove the pump cam retaining stud 98, and cover the opening 88 in the engine housing with a suitable cover plate. Conversely, any engine provided merely with an opening 88 in the housing and a suitably formed cam shaft, may readily have such a pump applied thereto at any time. Thus, this arrangement aids materially in carrying out developments hereinbefore referred to, which contemplate conversion of engines of standard mechanical con struction from operation as carbureter engines to operation as injection engines, or vice versa.

It will be evident that in so far as the mounting of multiple outlet pumps of the general character under consideration is concerned, the specific form and construction of the pump plunger and barrel and of the delivery and overflow passages may be varied, and in Figs. 7 to 11 there are shown by way of example other forms of pump having operating characteristics somewhat different from the form shown in Fig. 1, but equally applicable to installation in the manner illustrated in Fig. 6.

In Fig. '7 there is illustrated diagrammatically the plunger and barrel and associated parts of another form of pump in which the characteristics of injection at part load differ from those of the form of pump shown in Fig. 1.

In the present embodiment, the pump plunger 20a is provided with a delivery recess 520 which has control edges 56a and 58a parallel to each other and normal to the axis of reciprocation. This recess and the control edges advantageously extend circumferentially around the entire plunger. As in the previously described embodiment, the recess 52a is in constant communication with the pump chamber by means of a passage 54a in the plunger. The several delivery ports 42d, 44d, 46d, and 48d are arranged in the pump barrel in the manner previously described. The pump is provided with an inlet valve 38 and with a relief valve 2211 which in the present instance is loaded by a spring I02, the tension of which is adjustable by any suitable form of control adjustment, which in the present diagrammatic illustration has for convenience been shown in the form of an adjustable loading member I04 threaded into the head l2 of the pump to vary the spring load by turning movement of the loading member. i

As will be observed from the figure, the pump plunger at the beginning of its discharge stroke will force liquid trapped in the pump chamber out through the relief valve 22a until the control edge 46a comes into communication with the delivery port 46d. The delivery will continue as long as these ports are in communication and during any movement of the pump plunger between the time when ports 52a and 42d pass out of communication and ports 52a and 44d come into communication, overflow will again occur through the relief valve 22a. Similarly, alternating delivery and overflow periods will occur during the remainder of the discharge stroke of the plunger.

With this form of construction, rotational movement of the plunger will have no effect upon the duration or the timing of the delivery periods since in all positions of rotation of the plunger, delivery port 52a will come into communication with and pass out of communication with any given cylinder delivery port at the same times in the cycle of operation of the pump.

In this instance, control of the quantity of fuel delivered during each delivery period, in order to take care of part load operation of the engine, is efiected by varying the load on the relief valve, the minimum load on this valve required to enable delivery to be efiected being imposed thereon under idling load conditions and the load on the relief valve being increased as the load requirements of the engine call for more fuel to be delivered through the several delivery channels.

It is to be noted that in this form, as Well as in the form illustrated in Fig. 1, it is not essential that the relief valve be entirely closed during the delivery periods since the flow from the pump chamber. can simultaneously occur both through a delivery channel and the overflow channel, provided the resistance to flow through the overflow channel is sufficiently high to cause the required amount of fuel to be delivered through the delivery channel.

The principal difference in injection characteristics between the form shown in Fig. 7 and that shown in Fig. 1 is that in the structure shown in Fig. 7, part load injection continues through the same amount of cam travel as full load injection, the rate of injection being decreased for part load injection, whereas in the construction shown in Fig. 1, the rate of injection is maintained substantially constant at different loads (assuming the same pump speed) and the time of injection shortened as the load decreases.

It will be evident that in the form of pump shown in Fig. 7, the control pin associated 'With the plunger and its cooperating control rod may be dispensed with, but with this form of pump, the rotational control of the pump plunger may in some instances be advantageously used for a different purpose.

As shown in Fig. 7a, the control edges 56a and 58a may be made parallel and inclined so that as the plunger is rotationally adjusted to different positions, the timing of the delivery periods with respect to the cycle of operation of the pump will be changed, both as to commencement and termination of these periods. Thus, by the rotational control of the pump plunger, variable timing of injection with respect to the engine cycle may be very simply accomplished.

The control edges 56a and 58a need not necessarily be parallel but may, if desired, be arranged as shown in Fig. 7b, with a slight angle between them so that as timing of the injection periods is advanced upon increase in engine speed, the length of the injection periods are also varied. Such variation of the length of the injection periods may in some instances advantageously be used to aid in producing any desired delivery curve characteristic.

Referring now to Fig. 8, still another form is diagrammatically illustrated wherein the cylinder delivery ports are arranged in the same manner as in the previously described embodiments and in which the plunger is provided with a delivery recess 5211 similar to the one shown in Fig. 7. In the present instance, the barrel is provided with a relief or overflow port 1 communicating with an overflow passage I06, and the plunger is provided with a series of plunger overflow ports r1, 1'2, 1'3, n, and r5, longitudinally spaced along 5 the plunger and limited by control edges disposed at right angles to the axis of the plunger. A relief valve 22b is provided in the pump head, which valve in the present instance is made positively adjustable by means of the screw threaded control member I041). The discharge side of this valve may advantageously be connected into the common overflow channel I06, but this is not essential. In the operation of this pump, overflow from l5 the pump chamber during the initial portion of the discharge stroke takes place by way of the ports r-r1, and delivery does not commence until port 11 passes out of communication with port T2, at which time the delivery port 521) is in communication with port 42d. Delivery continues through port 42d until overflow is again established by communication between ports 1 and 12, at which time the delivery port 521) is in communication with port 44d. Further delivery periods through ports 46d and 48d are established by the remaining ports T3, T4, and 15 coming into and out of communication with the port 1'.

During the delivery periods the quantity of liqv uid delivered through the several delivery channels is determined by the arrangement for leakage flow past the control valve 22b, the adjustment of which operates to determine the quantity of fuel delivered. As in the form shown in Fig. 7, the present form operates to vary injection at part load by varying the rate of delivery rather than the duration of the delivery periods. It is believed it will be obvious from the previous description in connection with Figs. '7, 7a and 7b that the rotational adjustment of the plunger in 40 the present instance may be utilized to vary injection timing and a1so,.if desired, the duration of the periods of injection by suitably inclining the control edges of the plunger delivery port. In Fig. 9 still another form is illustrated which in effect combines the features of construction shown in Figs. '7 and 8. In this arrangement, the plunger and barrel construction is the same as in Fig. 8 but instead of having rigid adjustment of the overflow control valve, the valve 220 is loaded by means of a spring [020 backed by an adjustable loading member lMc. It is believed that it will be clear from the preceding description in connection with Fig. 8 how the overflow and delivery periods are eflected by plunger movement.

.55 The difference in operating characteristics of the present form in comparison with that shown in Fig. 8 is that in the present form overflow through the control valve 220 does not take place until a predetermined pressure is built up in the pump chamber, which pressure may be made the desired value by suitable adjustment of the loading member L040. On the other hand, in the form shown in Fig. 8 there is normally always some leakage flow past the control valve 22b.

. 5 In Fig. 10 still another form of construction is shown in which the timingand duration of the delivery periods is controlled by means of a mechanically actuated overflow valve. As shown in this figure, the several cylinder overflow ports are arranged in the usual manner and the plunger overflow port 52d is similar to that shown in Fig. '7. The pump cam member M8 is provided with a valve operating cam ii iii which may be in the form of a square camhaving lifts iliia, iitb, Mile, and

HM, and which further is advantageously necessity for a separate suction valve such as that 10 shown at 38 in Fig. 7.

With respect to the use of a suction valve,it

will be apparent that in the forms of construction shown in Figs. 8 and 9, where a plunger controlled overflow, in addition to the adjustable overflow, 15

is provided, the plunger controlled overflow may be used in lieu of a separate suction channel for filling the pump chamber on the suction stroke.

In any of the forms shown in Figs. 8 to 10 the separate suction valve may obviously be employed 20 if desired.

In the form shown in Fig. 10 it will be apparent that the length of the overflow periods, which in turn determine the length of the delivery periods, and also the rate of flow during the overflow 25 periods, may be determined by the contour and axial position of adjustment of the'cam 0. It further will be apparent that the pump shown in Fig. 10, depending upon how the cam is adjusted, may be operated so that a determined amount of overflow occurs through the valve 22d during a delivery period, or so that the valve is entirely closed during the delivery periods and is opene only for effecting termination of delivery.

' It is believed that it will be obvious that the several different modifications of pump plunger, barrel, and overflow parts illustrated in Figs. 7 to 11, inclusive, may be incorporated in a pump, mounted in the manner illustrated in Figs. 5 and 6, in lieu of the plunger, barrel, and overflow 40; parts shown in the modification illustrated in Figs. 1 to 5.

Referring again to-the structure shown in Figs. 1 to 6, it will be observed that in so far as the precision parts of the pump are concerned, which 45 determine the character and duration of the delivery and overflow periods, these parts constitute a unitary assembly consisting of the pump head with the attached pump barrel and pump plunger, which unit is removably secured to the pump 50 casing l0.

While in most instances it is preferable to detachably secure the pump casing ID to the engine, it will be apparent that if desired this casing part may be formed integrally with the engine 55 part such as the gear cover and in case it is not desired to use a fuel pump on the engine, such a casing part, adapted to receive the operating parts of the pump, may readily be closed ;by means of any suitable cover plate removably secured to the 60 top of the pump casing in lieu of the pump head with which the pump operating parts, with the exception of the pump cam, are assembled as a unit.

. From the foregoing description of the several 65 embodiments illustrated it will be apparent that numerous different specific forms of pump structure may be employed within the scope of the invention, which is accordingly to be understood as embracing all forms of structure falling within to the scope of the appended claims and is not to be limited to the embodiments herein shown by way' of example.

Certain features involving the novel mounting of the fuel pump on the engine, which are dis- 7 1 to said outlets, said plunger being ported to place different delivery passages in communication with said chamber at difierent times during the discharge stroke of the plunger, and overflow means providing for escape of liquid from said chamber to provide for overflow from said chamber during a portion of each period when a delivery passage is in communication with the chamber, said overflow means including a passage leading from said chamber and means independent of the pump plunger for controlling flow through the last mentioned passage.

2. A pump having a plurality of delivery outlets, including a cylinder and a pump plunger reciprocably mounted therein to provide a pump pressure chamber in which delivery pressure is created by movement of said plunger, a plurality of delivery passages leading from said chamber to said outlets, said plunger being ported to place different delivery passages in communication with said chamber at difierent times during the discharge stroke of the plunger, overflow means including cylinder and plunger overflow ports for determining the timing and duration of overflow periods, and additional overflow means operative during delivery periods for determining the quantities of liquid delivered during the delivery periods.

3. A pump having a plurality of delivery outlets, including a cylinder and a pump plunger reciprocably mounted therein to provide a pump pressure chamber in which delivery pressure is created by movement of said plunger, a plurality of delivery passages leading from said chamber to said outlets, said plunger being ported to place different delivery passages in communication with said chamber at different times during the discharge stroke of the plunger, overflow means including cylinder and plunger overflow ports for determining the timing and duration of overflow periods, and adjustable additional overflow means operative during delivery periods to determine the quantities of liquid delivered, and the pump chamber pressure during said delivery periods.

4. A pump having a plurality of delivery outlets, including a cylinder and a pump plunger reciprocably mounted therein to provide a pump pressure chamber in which delivery pressure is created by movement of said plunger, a plurality of delivery passages leading from said chamber to said outlets, said plunger being ported to place different delivery passages in communication with said chamber at difierent times during the discharge stroke of the plunger, overflow means including cylinder and plunger overflow ports for determining the timing and duration of overflow periods, and additional overflow means comprising an adjustable overflow control member arranged to provide an overflow orifice constantly open during the discharge stroke for determining the relation between the quantities of liquid discharged through said additional overflow means and through said delivery passages during the delivery periods occurring in the intervals between the overflow periods established by the first mentioned overflow means.

5. A pump having a plurality of delivery outlets, including a cylinder and a pump plunger reciprocably mounted therein to provide a pump pressure chamber in which delivery pressure is created by movement of said plunger, a plurality of delivery passages leading from said chamber to said outlets, said plunger being ported to place diflerent delivery passages in communication with said chamber at different times during the discharge stroke of the plunger, overflow means including cylinder and plunger overflow ports for determining the timing and duration of overflow periods, and additional overflow means including a spring loaded valve adapted to be opened by pump chamber pressure during the periods when overflow through the first mentioned overflow means is cut off.

6. A pump having a plurality of delivery outlets, including a cylinder and a pump plunger reciprocably mounted therein to provide a pump pressure chamber in which delivery pressure is created by movement of said plunger, a plurality of delivery passages leading from said chamber to said outlets, said plunger being ported to place different delivery passages in communication with said chamber at different times during the discharge stroke of the plunger, overflow means including cylinder and plunger overflow ports for determining the timing and duration of overflow periods, additional overflow means including a. spring loaded valve adapted to be opened by pump chamber pressure during the times when overflow through the first mentioned overflow means is cut off and a control member for varying the spring load on said valve to regulate the delivery pressure generated by the pump plunger during said times.

7. A pump having a plurality of delivery outlets, including a cylinder and a pump plunger reciprocably mounted therein to provide a pump pressure chamber in which delivery pressure is created by movement of said plunger, a plurality of cylinder delivery ports and passages leading from said ports to said outlets, said plunger having port means for placing different cylinder delivery ports in communication with the pump chamber at difierent times during the discharge stroke of the plunger to provide spaced delivery periods during said stroke, the timing and duration of communication between the plunger port means and said cylinder delivery ports determining the timing and duration of said delivery periods, and overflow means operable to discharge liquid from the pump chamber during the periods between said spaced delivery periods.

8. A pump having a plurality of delivery outlets, including a cylinder and a pump plunger reciprocably mounted therein to provide a pump pressure chamber in which delivery pressure is created by movement of said plunger, a plurality of cylinder delivery ports and passages leading from said ports to said outlets, said plunger having port means for placing different cylinder delivery ports in communication with the pump chamber at different times during the discharge stroke of the plunger to provide spaced delivery periods duringsaid stroke, the timing and duration of communication between the plunger port means and said cylinder delivery ports determining the timing and duration of said delivery periods, and overflow means including a spring loaded overflow valve arranged to be opened by specter pump chamber pressure for limiting the maxi mum pressure in said chamber during delivery periods ag'nd for discharging liquid from said chamber during the periods between said de= livery periods.

9. A pump having a plurality of delivery outlets, including? a. cylinder and a pump plunger re ciprocohly mounted therein to provide as pump pressure chamber in which delivery pressure is created by movement of said plunger, 9, plurality of cylinder delivery ports and passages leading from said ports to said outlets, said plunger lisv ins port means for placing (llfffiifillt cylinder de livery ports in communication with the pump ill chember at (lifierent times during the discharge stroke of the plunger to provide spaced delivery periods during said stroke, the timing and slurs-t tion of communication between the plunger port means and the delivery ports determining the timing and duration of said delivery periods, and overflow means including o spring loaded overflow velve arranged to be opened by pump chem bar pressure and on adjustable control member for varying" the spring load on said overflow valve.

ill. A pump having a plurality oi delivery out lets, including o cylinder and a pump plunger reciprocobly mounted therein to provide at pump pressure chamber in which delivery pressure is erected by movement of said plunger, a plurality of delivery passages leading" from said chamber to said outlets, said plunger having port means including, a, port for placing said delivery pas sages successively in commuuicotion with the pump chamber during the dlsclirorge stroke of the plunger, said port means being shaped and orranged-tc provide delivery periods or constant duration, and overflow means adjustable to regulate the pump chamber pressure genersted by the plunger during said delivery periods, whereby to a control the quantities of liquid delivered during said periods.

11. A pump having it plurality of delivery out lets, including a, cylinder and a pump plunger re clprocobly mounted therein to provide a pump 45 pressure chamber in which delivery pressure is created by movement of said plunger, a plurality of delivery passages leading from said chamber to said outlets, said plunger having port means including a. port for placing sold delivery postill ' 50 sages successively in communication with the pump chomber during the discharge stroke of the plunger, said port means being" shaped and arranged to provide delivery periods of constant duration, and overflow means including a spring v 55 loaded overflow valve arranged to be opened by pump chamber pressure and an adjustable con trol member for varying the spring load on said valve to regulate the pump chomber pressure developed by the plunger, whereby to control the 0 quantities of liquid delivered during said delivmy periods.

12. A pump having a plurality of delivery outlets, including a, cylinder and a pump plunger re ciprocably and rotatably mounted therein to provide a pump pressure chamber in which delivery pressure is created by movement of said plunger,

a plurality of delivery passages leading from said chamber to said outlets, sald'plunger having a delivery port in constant communication with the 70 pump chamber for successively placing said delivery passages in communication with the pump chamber, said port being shaped to vary the timing of communication of each of the several delivery passages with the pump chamber as the pump plunger is turned to different positions of rotation, whereby to vary the timing of the de livery periods, and adjustable overflow moons for placingsold delivery passages in communication with the pump chamber, said port beine she-peel to very the timing and duration of the delivery periods as the pump plunger is turned to difierent positions of rotation, and adjustable overflow means for regulating the pump chamber pressure developed by sold plunger during said delivery periods.

it. A pump having a plurality of delivery outlets, including a. cylinder and or pump plunger re clproccbly mounted therein to provide er pump pressure chamber in which delivery pressure is created by movement of said plunger, a plurality of delivery passages leading from sold chamber to sold outlets, said plunger being ported to place said delivery passages in commurllcotlon with the pump chamber at difierent times during the dis charge stroke of the plunger, and overflow means including o, valve and mechanical volve actuating means for holding sold valve open against pumpchamber pressure to permit overflow from scold chamber during the times when said delivery passages are out of communication with the chamber: i

15. A pump having a plurality of delivery out-- lets, including a cylinder and a, pump plunger reciprocebly mounted therein to provide a pump pressure chamber in which delivery pressure is created by movement of sold plunger, 2. plurality of delivery passages leading from said chamber to said outlets, said plunger being ported to place said delivery passages in communication with the pump chamber at different times during the discharge stroke of the plunger, and overflow means including o valve, mechanical valve actuating means for opening said valve against pump chamber pressure and means for adjusting said valve actuating means to vary the extent to which sold valve is opened.

16. A pump having a plurality of delivery outlets, lncluding a cylinder and a pump plunger reciprocably mounted therein to provide a. pump pressure chamber in which delivery pressure is created by movement of said plunger, a, plurality of delivery passages leading-from said chamber to said outlets, said plunger being ported to place said delivery passages in communication with the pump chamber at different times during the discharge stroke of the plunger, is liquid supply passage communicating with said pump chamber, a valve for controlling said passage, said valve being arranged to be opened against pump chamber pressure and mechanical actuating means for opening said valve s plurality of times during each cycle of operation of the pump to provide for admission of liquid to the pump chamber during the suction stroke and to provide overflow of liquid from. said chamber in a, plurality of difi'erent positions of reciprocation of the plunger during its discharge stroke.

TQRBJdRN vm'ron mue'rnoM. 

